MILWAUKEE — Jeff Green took advantage of his opportunity to take over during a critical stretch for the Celtics against the Milwaukee Bucks. He had a partner in doing so Monday night at the BMO Harris Bradley Center.

Kelly Olynyk has been wildly inconsistent during his rookie season, following up sparkling games with duds. Since his 25-point performance Jan. 17 against the Lakers, he had averaged 5.6 points in 11 games, including a pair of 1-point efforts.

With the Celtics holding a precarious 2-point leading entering the fourth quarter, Olynyk scored 10 points and grabbed five rebounds while Green streaked his way to another stellar night as the Celtics bounced back with an impressive 102-86 victory in front of a sparse crowd on a frigid night in Milwaukee.

Green scored 29 points, 27 after the first period, and he tallied 9 points as the Celtics began the fourth quarter with a 21-8 run to seal the game. And after losing 19 of 22 games, the Celtics have won four of five and are generating momentum before the All-Star break.

Coming off a disappointing loss Sunday to Dallas, the Celtics, usually the team blowing late leads, outscored the undermanned Bucks, 32-18, in the final quarter, shooting 63.6 percent in that stretch. Green and Olynyk teamed for 21 points.

Meanwhile, Eastern Conference Player of the Week Jared Sullinger overcame a slow start to notch a double-double (13 points, 10 rebounds), nabbing seven rebounds in the final period.

“That group was playing so well, I didn’t really mess with it,” Celtics coach Brad Stevens said of his fourth-quarter lineup. “We’ve talked about this before but I [like] Kelly and Jared’s ability to pass, play, score. If they can defend and rebound together at the end of that game, it’s great to have them in because they make so many basketball plays. That was a positive to see both of those guys end up with double-doubles.”

Olynyk looked comfortable down the stretch, playing without overthinking. He drained an open 3-pointer off a Jerryd Bayless dish for a 79-69 Celtics lead with 10 minutes left. He staved off a mini-Bucks run with a lunging layup for a 9-point lead at the 6:56 mark and then finished his personal flurry with 5 consecutive points for a 91-76 lead.

The Bucks, playing without four rotation players and easily headed for the league’s worst record (9-42), were finished.

“[The Bucks] were helping a lot on Jeff in the fourth quarter and I was able to get a couple of open shots as well,” Olynyk said. “I’m comfortable playing with almost everyone now.”

Without Rajon Rondo (knee rest) and Avery Bradley (sprained right ankle), the Celtics received six assists apiece from Phil Pressey and Bayless while Green took control of the offense in stretches by playing point guard and creating his own show. Green was 10-for-18 shooting with 27 points in the final three periods, relying on his swooping layups or midrange jumpers.

Green, the master of the unexpected breakout game, is averaging 24.8 points in his past four games.

“I kept shooting, my confidence didn’t sway away and I’m confident in every shot I put up,” he said. “I just wanted to continue to try to get to the rim because it’s going to open everything else for me. With my abilities on the court, I’m able to do a lot. I’m going to use my abilities and all the work I put into this game of basketball every game, and if Coach wants me [to take over] then I am going to do it.”

It wasn’t a cinch victory over an ailing team. The Celtics struggled with the Bucks for the first three quarters, falling behind, 66-63, after a Gary Neal 3-pointer with 2:25 left in the third. Green responded with a jumper and Chris Johnson continued his torrid long-range shooting with a 3-pointer and Olynyk finished off the 7-0 run with a layup. The Celtics never trailed again.

The only blemish was an eye injury suffered by Brandon Bass, who was poked by Zaza Pachulia, sustaining a corneal abrasion in the third quarter. Bass sparked the Celtics in the early going with 12 first-quarter points after the Celtics fell behind by as many as 7, but they rallied to take a 49-46 lead at the break.

And the victory avoided what would have been an embarrassing overall performance against the league’s worst home team. Two of the Bucks’ nine victories are against the Celtics, including the home opener at TD Garden Nov. 1.

Also, Milwaukee was without four rotation players — Ersan Ilyasova, O.J. Mayo, Caron Butler, and Larry Sanders — because of injury and then lost John Henson to a sprained right ankle in the fourth quarter.

The Bucks officially clinched a losing season and are a stunning 31 games behind the Indiana Pacers in the Central Division.

“We need the All-Star break,” Bucks coach Larry Drew said. “We got hurt with turnovers tonight. That was really one of the points of emphasis going into this game against the Celtics. We didn’t want to give them any easy baskets. We just turned the basketball over. It just put us in such a dilemma.”